Hawk is here, yay!

[Megadan]

Thank ya kindly gentlemen.

My next oko mounting solution is to modify a carb adapter used for the horizontal engines that can bolt to the stock intake manifold. Needs to be ported from 28 to 30mm and the mount holes drilled through as they come threaded for an m6 bolt. Not the most graceful solution, but it should work and be cheap and simple.

[Emerikol]

Cheap and simple have a grace and elegance all their own...

[Megadan]

Originally Posted by Emerikol

Cheap and simple have a grace and elegance all their own...

Well, the biggest issue I have is all of the rubber. Somebody posted a link to a metal intake at some point that I would love to use since the adapter is a rubber mount itself.

[Megadan]

Kind of a side note, but I finally got around to installing my rear LED indicators to match the front, and just out of curiosity I tried them without changing out the relay. They don't really blink faster, and if they do its such a small increase that it is barely noticeable. I wonder if they installed electronic relays in place of the old beeper relay setup of previous years, because I never had a beep and I dont have any fast flash issues now either.

Also, since I forgot, here is said carb adapter in question. http://m.ebay.com/itm/Carb-Flange-In...-/231772456484

[Megadan]

I got my new jets in. I have still been having inconsistent fueling issues with my Fakuni, so I took it apart, cleaned it, and blew out the jets and passages with my compressor and needle nozzle. Doing that combined with the aftermarket exhaust and intake mods has made things much easier to determine. I must have had a partial block in my pilot circuit, because now the 30 pilot jet is showing itself to be too big. Only about 5/8ths of a turn on the mixture screw. Luckily I have a 25 pilot sitting here and since I just got my 120 main, I am going to go ahead and install those and start fresh.

I am also going to do a little experimenting with the intake side. I do want to try and retain the airbox, and I have some dual layer woven foam filter sheeting that was being thrown out at my work to make a filter or 24 with. It is an oiled dual density filter used for paper dust in our trim vacuum machines at work, so it's filtration ability is unquestioned. I will post some pics later as I tinker. I also got my Uni filter in for the Mikuni so I can remove the airbox and determine just how I want to modify it. Likely I will simply trim the bottom rear corner that is trying to be best buds with the exhaust and epoxy some sheet aluminum or PVC sheeting over the hole I cut out.

[Megadan]

So, my experimentation had inconclusive results, BUT I will note that my stock intake tube has a kink in it that may have limited the results.

That said, there was still a slightly noticeable improvement in throttle response and bottom end pull with this foam in place of the stock filter. I think the lack of any top end feel can be blamed on said kink in the intake tube. There was a definitely increase in intake noise though lol. Not annoying, but definitely noticeable.

Essentially I cut away the seal from the stock air filter (sacrificed in the name of science) and put it back in place and sandwiched the foam between it and the air filter clamp. I intentionally made it larger so that the screws for the filter clamp went through the foam element just to ensure it was anchored. Being an oiled foam type filter, it is much more waterproof than the paper filter, but due to the type of foam I used, this would not be a washable solution. However, Uni does sell sheets of filter foam for custom filter applications, so this idea could be applied using that and you could have a washable, reusable filter. Weather stripping could also be used in place of the air filter seal to help pinch the foam in place, but I would also put some sort of strip that helps secure and locate the filter to the inner edge of the filter clamp, much like the paper element sticks through it.

[pete]

i have put zip ties around a intake boot before to get
it back into shape... got rid of half of the kink...


...

[Megadan]

Originally Posted by pete

i have put zip ties around a intake boot before to get
it back into shape... got rid of half of the kink...


...

I actually did consider doing something similar with a hose clamp. I am sticking with the pod filter for now so I can pull the airbox anyway. I want to trim up and epoxy a section of aluminum or plastic where the exhaust hits just to buy it a little room.

[Megadan]

In other news, I did a few other changes to the bike. I did a short little video on it, and forgive my space cadet nature and problems speaking. I was a bit tired lol.




Oh, and dirty bike beauty shot.

[Megadan]

After playing with jet sizes with the exhaust and intake I have settled on 27.5 pilot and 117.5 main. Needle clip 1 down from center.

The 30 pilot jet was just too big. After playing with the idle and mixture screws I finally got the best results on about 5/8ths of a turn on the mixture screw to get the best idle, For cuiosity I tried a 25 pilot, and while the mixture screw ended up in the best position right at about 1 5/8 turns out, it would pop and buck at light throttle, so it was just a tad too small. The 27.5 pilot sets the mixture screw just about 1 to 1 1/4. Once I find it's happy place I will dismount it and count the turns.

The main jet was a compromise. The 115 main works well, but was just a tad lean, but not terribly - plug was almost clean, but no signs of getting hot, if I was going for fuel economy, then it's probably the right main to have. I ran a 120 main, but it was just the opposite end of the spectrum and a tiny bit rich. With a 25 pilot the 120 main fueling was spot on, so for a hot climate this might be a good combination. With the 27.5 or 30 pilot it would just slighly load up, so if you rolled off WOT occasionally you would get a teeny tiny bit of surge. Since I bought some "between" jets laying around I decided to try the 117.5. It's perfect.

As far as the needle position goes, I initially had it set in the 4th position and moved it back to center. Since my bike spends the most time in this range and the weather is still on the hot side I chose to put it back in the 4th slot. When it gets cool at night it runs better, and on the hotter part of the day it helps it run just a bit cooler.

So obviously, now that I have my Mikuni sorted I will get my intake stuff for the OKO in a week or so lol.

I know there can be a tiny bit of variance between engines, but I have noticed that my bike really lacks power up top. Even reaching 7000rpm after the mods, it definitely falls on its face still, but with the exhaust and intake it struggles a lot less.

What my bike really gained was low end and mid-range power, and a TON of it. The 17/43 sprocket combination felt a little over geared on the stock intake and exhaust, but with both my foam element on the stock airbox w/airbox mod and the Uni Filter especially combined with the exhaust, this thing tractors along. It used to almost stall trying to idle in first gear (about 5-6mph) but now it will chug along without a care. I also find that I can be cruisin along at 35 in 4th gear and throttle on to pass without needing to downshift, where before I could do this but it took its sweet time. Rolling on the throttle hard in first gear at about 10mph damn near threw me back hard enough that I really had to hang on, and I felt myself slide back in the seat. I honestly believe I could gear this bike down even more for road use without really losing too much in the way of top speed. I won't, because I kind of like it where it is... but I could.

At this point I have couple of thoughts based on what I have experienced with the modified bike. This engine definitely has a lot of charge velocity at lower RPM but is definitely being choked off up top. Any gains from cleaning up the intake and exhaust ports on the head will definitely help on the top end. That said, I am almost wondering how well the engine will handle the OKO/PWK style flat slide with it's true 30mm bore. I don't doubt that there will be some sort of gain from the increased airflow, but I don't think the true potential of the carb will be seen until the headwork is done. Obviously, I won't know for sure until I can install it.

Oh, and new top speeds reached. 70mph on a mild downhill, 64-65 on flat ground (had a slight cross wind causing it to dance between the two). It will now cruise at 60 without the throttle being pegged. Goal reached. It still slows down to about 55 on steeper hills, but you can only ask so much from 230cc's

[pete]

is it possable for you to fit up a wide band AF gauge to set the carb up...
i thought I had the Koso/OKO right... lot stronger power though the whole rev range
motor ran great everywhere...
but once the AF gauge was fitted... god dam it was rich... these carbs seem to run very well on the rich side...

my AF ratios are after setting with the gauge...
idle... 14.3 - 14.8
light cruse 13.7 - 14.2
light acceleration higher gears 13.2 - 13.6
acceleration from 1/3 to 2/3 throttle 12.9 - 13.4
WOT 12.4 - 12.9... see the power jet really richen up the mixture at
full throttle..

edit....
these numbers are still a tad on the rich side... but thats what i want
my bike is never at a cruse... on & off the gas hard all the time accelerating
or brakeing.. A/F ratio is set to suit what the bike is used for...
thats the great thing useing a A/F gauge to set the jetting..

i had to change the needle to a leaner one "slower tapper" to
get the mid range ok...
went from a 1mm point to a 1.4mm point...
mikuni needles seem to be the best match.
57mm long with a 2.5mm top DIA...

A A/F gauge is worth useing.
What you think you have & what you really have can be 2 diffrent things...

.

[Megadan]

Originally Posted by pete

is it possable for you to fit up a wide band AF gauge to set the carb up...
i thought I had the Koso/OKO right... lot stronger power though the whole rev range
motor ran great everywhere...
but once the AF gauge was fitted... god dam it was rich... these carbs seem to run very well on the rich side...

my AF ratios are after setting with the gauge...
idle... 14.3 - 14.8
light cruse 13.7 - 14.2
light acceleration higher gears 13.2 - 13.6
acceleration from 1/3 to 2/3 throttle 12.9 - 13.4
WOT 12.4 - 12.9... see the power jet really richen up the mixture at
full throttle..

i had to change the needle to a leaner one "slower tapper" to
get the mid range ok...
went from a 1mm point to a 1.4mm point...
mikuni needles seem to be the best match.
57mm long with a 2.5mm top DIA...

A A/F gauge is worth useing.
What you think you have & what you really have can be 2 diffrent things...

.

I have a home made tailpipe sniffer wideband that I can use, but it's not very convenient to actually ride around with. I know my bike is a bit on the rich side, but not by much. Plug checks (i have a whole mess of coppers I use to help tune lol), engine behavior, and other factors have me to a point that I am pretty sure of where my bike is fueling wise. Would I like a wideband installed on the bike? Absolutely.

My methodology involved a lot of carb removal to do some experimentation. Aside from plug chops, there is also behavior.

Example. A 110 main with the intake and exhaust showed clear signs of being lean at WOT, even with the too big 30 pilot jet taking up some slack. On the opposite end of the spectrum, the 125 pilot was too rich - especially with the 30 pilot and would instantly bog when full throttle was attempted.

I left the 125 main in place and put in a 25 pilot. The 25 pilot, even with the tiny bit of extra fuel from the too big main, was a touch on the lean side at light throttle slow speed cruising - showing the classic signs of backfires, pops, hesitation and herky jerky throttle. The 125 main was still too big and would bog down at wide open.

I left the 25 pilot in place and dropped to a 120 main. slightly too lean pilot jet combined with a slightly too rich main. No bog at wide open anymore, but would have a slight surge once in a while when rolling off wide open. I left in the 120 main and installed the 27.5 pilot. All light throttle slow speed hesitation was gone, throttle is smooth and idle mixture takes 1 turn or more out. However, the occasional stumble rolling off of wide open ever so slightly cam back.

Leaving the 27.5 pilot in place, because it's perfect, I dropped down to the 115 main. Excellent behavior all around, top end of the throttle spectrum was responsive, no roll off surge. I then did a plug chop on a fresh plug and the plug was slightly off-white. This is when I put in the 117.5, and after a plug chop on that jet - a dark tan/brown. Also, the tried and true "top speed" method gave the nod to the 117.5 main, able to achieve an average of 1-2mph on the same road, on the same day, in more or less the same temp and humidity. I can swap main jets in about 10 minutes even on a hot bike lol.

It may be a bit on the rich side, but not by much. With aircooled motors I always favor the richer side of things, at least in the hot months here. That is also why I moved the needle up one notch. I am going to go ride it again tonight and see how it behaves in cooler weather.

If I were to put the 115 main back in and set the needle in the center, I am certain this bike would be more or less dead perfect for what I call "OEM" carb tuning. Aka ever so slightly lean, but not too lean, and get the ultimate fuel economy. I am fairly certain I can move the needle back to center with the 117.5 and be fine, and I may still do so, if for any other reason than fuel economy. I will wait and see how it behaves in cooler weather.

As far as the OKO/PWK carb that I have. It already has a Mikuni needle jet in it. I will have to measure it to get an idea of the taper.

[Megadan]

Cooler weather report on carb setup. While a tad rich during the hotter part of the day (high 80's to low 90's), with the air temp at 68F the bike definitely perks up a tiny bit, but never once showed a sign of being lean.

New flat ground, no wind (rare around here) top speed. 66.7mph via GPS without being in a tuck. Compare that to a "tuned" carb with the stock exahust and intake setup and the same gearing, which had a personal best of 63mph with me tucked down. and barely 60 with me sitting upright.

She also now happily cruises at 60mph all day long at a bit less than or equal to 3/4 throttle. I still wouldn't want to take a long trip pushing it that hard, but it should handle the 8 miles of highway I normally take to work just fine. Time to finally get around to an oil cooler. I kept putting it off for one reason or another, and now I have no excuse.

[Megadan]

First higway ride to work with the new setup. It handled the bigger hills with ease, and never once did I slow nelow 60, or have to peg it to maintain. Hovers right at 6200 rpm and sings along rather loudly lol.

As much as I want to simply wear out the knobby tires, they arent very good for sustained higway riding. Now I just need to figure out what tires to go with.

[Weldangrind]

I love how compulsive you are with jet tuning, Dan. What sort of tool do you use for pilot mixture adjustment? Can you show us?